Acidfaststnmlk
This test uses a special staining technique to detect acid-fast bacteria (such as Mycobacterium bovis) in milk samples, primarily used to screen for bovine tuberculosis.
{"Detects acid-fast bacteria that cause tuberculosis in cattle","Uses a specialized staining method (Ziehl-Neelsen or auramine-rhodamine)","Helps ensure milk safety for human consumption","Positive results indicate potential bovine tuberculosis infection","This test screens milk, not human blood or serum"}
Key facts at a glance
- LOINC
- 90269-2
- Short code
- AFB-MILK
- Synonyms
- Acid fast Stn Mlk
- Category
- chemistry
- Sample
- serum
- Container
- Sterile leak-proof container for milk; serum separator tube (SST) or plain red top tube for serum
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- 2.5 N/A – 6.5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- acid-fast-stain
- CPT
- 87015
- SNOMED
- 122442009
- Specimen volume
- 2-5 mL milk or 1-2 mL serum
- Stability
- Refrigerate at 2-8°C; process within 24-48 hours. Do not freeze milk samples.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
What is this test?
The Acid-Fast Stain test is a laboratory technique used to detect acid-fast bacteria, primarily Mycobacterium species, in milk samples. These bacteria have a unique waxy cell wall that resists standard staining methods. The test uses special dyes (like carbol fuchsin in Ziehl-Neelsen stain or fluorochrome stains) that penetrate this waxy coating, allowing technicians to visualize the bacteria under a microscope.
How is the test performed?
A milk sample is smeared onto a slide and treated with special stains. The sample is then heated (in traditional methods) or treated with chemicals to allow the stain to penetrate the bacterial cell wall. After washing with an acid-alcohol solution, only acid-fast bacteria retain the red stain (Ziehl-Neelsen method) or fluoresce under UV light (fluorochrome method). The slide is examined under a microscope to identify the characteristic rod-shaped bacteria.
Why is milk tested for acid-fast bacteria?
This test is primarily used in food safety and veterinary public health to screen for bovine tuberculosis (caused by Mycobacterium bovis). While pasteurization kills these bacteria, unpasteurized (raw) milk can transmit the infection to humans. Testing helps ensure the milk supply is safe and helps control bovine tuberculosis in dairy herds.
Reference range
Adult: 10-40 U/LN/A
No fasting required. For milk sample: collect mid-stream milk in sterile container. For serum: follow standard venipuncture protocol. Inform laboratory of any recent antibiotic therapy or TB exposure.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Is this test for checking my health?
Why does the order show 'serum' as the sample type?
Is raw milk safe to drink?
What happens if the test is positive?
Sources
- 1
- 2
- 3FDA - Milk SafetySource
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy